New achromatic logic in LCH is not sufficient for all achromatic colors

[facelessuser]

This is due to recent changes on main.

> new Color("white").to('lch').coords
[ 100, 0, null ]
> new Color("gray").to('lch').coords
[ 53.58501345216902, 2.220446049250313e-14, 270 ]
> new Color("darkgray").to('lch').coords
[ 69.23779560557699, 5.978733960281817e-14, 338.1985905136482 ]

I would argue we don't need a super tight check for achromatic chroma. If the expectation is exact zero for null hue or nearly approaching such, that will not be sufficient. As a matter of fact, I would suggest being a bit loose to account for errors introduced by converting to other spaces and round tripping. Some conversion algorithms may be less accurate than others in some cases.

[LeaVerou]

The only actual change in logic was that the epsilon is now smaller.
What is the minimum epsilon that would not have these issues?